DESCRIPTION (Adapted from the Abstract): The purpose of this project is to elucidate the function and significance of the robust electrical rhythmicity of the neurons in the inferior olive and their relation to the temporal and spatial organization of skilled movement. In this experiments, the Principal Investigator will employ multiple-microelectrode recordings of Purkinje cell complex spike activity in vivo while rats perform skilled movements with their oro-facial and limb muscles. The central working hypothesis of this project is that the muscle synergies required for coordinated movement of multiple limbs depend upon the rhythmic activity of the highly parallel projection from the inferior to the cerebellum. This activity physically and rhythmically modulates motor systems. Indeed, that damage to the inferior in humans animals permanently destroys the temporal and spatial structure of skilled movement is firmly established. Using highly controlled experimental conditions with rats, the Investigator will address the following questions: Does the olivocerebellar system organize a forepaw-tongue movement synergy? If so, how? Does the olivocerebellar system temporally organize a spatially-guided movement produced by bilateral musculature? If so, how? What relationship do the two major afferent systems of the cerebellum, the climbing and the mossy fibers, have in organizing movement? Does uncontrolled rhythmic activity within the inferior olive drive pathologically rhythmic movements, such as those seen during a myoclonic seizure?